中国花鲈在长江口不同亚生境中的栖息特征

Habitat traits of Lateolabrax japonicus in different subhabitats of Yangtze River Estuary

为探究中国花鲈(Lateolabrax maculatus)在长江口盐沼湿地不同亚生境的选择利用情况,该研究于春、夏、秋、冬4个季节对九段沙湿地的潮沟、海三棱藨草(Scirpus mariqueter)植被区和光滩3种亚生境进行插网调查采样。结果显示,中国花鲈为长江口盐沼湿地优势种,在春、夏和秋季其空间生态位宽度逐渐减小,而在3种亚生境中的时间生态位宽度依次减小。中国花鲈的数量分布具有明显的时空差异,即春季最多,秋季最少;潮沟中最多,植被区次之,光滩最少。进入长江口盐沼湿地的中国花鲈以幼鱼为主,且集中在春季。潮沟区小规格个体所占比例较高,但光滩和海三棱藨草植被区大规格的个体所占比例高于潮沟。中国花鲈的平均摄食等级在潮沟亚生境呈现从春季到冬季逐渐增大的趋势;在光滩亚生境呈现从春季到秋季逐渐增大而到冬季骤减的趋势;在海三棱藨草亚生境呈现夏季最大,秋、冬季逐渐减小的趋势。中国花鲈平均摄食等级在春、夏、秋季表现为海三棱藨草>潮沟>光滩;而冬季较其他季节特殊,中国花鲈平均摄食等级表现为潮沟>海三棱藨草>光滩。

In order to explore the selection and utilization of Chinese seabass(Lateolabrax maculatus)in different subhabitats of the salt marsh of the Yangtze River Estuary,we investigated three subhabitats of tidal creek,mudflat and Scirpus mariqueter vegetation area,and took samples in spring,summer,autumn and winter.The results show that L.maculatus was the dominant species in that area.The spatial niche breadth of L.maculatus decreased gradually in spring,summer and autumn,while the temporal niche breadth was in a descending order of tidal creek>S.mariqueter vegetation area>mudflat.There was a significant spatial-temporal difference in the population distribution of L.maculatus(highest in spring but lowest in autumn;most in tidal creek,followed by S.mariqueter vegetation area and mudflat).The majority of L.maculatus entering the Yangtze River Estuary were juveniles,which occurred mainly in spring.Small-size individuals preferred to inhabit in tidal creek,while large-size ones preferred to inhabit in mud-flat and S.mariqueter vegetation area.For the average feeding grade of L.maculatus,it increased gradually from spring to winter in tidal creek,and increased gradually from spring to autumn but decreased sharply in winter in mudflat,reaching the maximum in sum-mer and decreased gradually in autumn and winter in S.mariqueter vegetation area.In spring,summer and autumn,the average feed-ing grade of L.maculatus was in a descending order of S.mariqueter>tidal creek>mudflat.However,it was in a descending order of tidal creek>S.mariqueter>mudflat in winter.